Down Time

The down time statistics are based on individual fault reports. In Table 1 I give the general down time statistics for period 36. A total of 74 fault reports were submitted, with an average time lost of 14 min per fault, for a total down time of 0.8% (1.1% on scheduled observing nights). Of these, 47 reported no time lost, 24 reported $<$ 2 hrs lost, and 3 reported 2 or more hrs lost.

Table 1: Technical down time statistic period 36: 2007-10-01 to 2008-04-01

Night included	Time lost	Nights	Percentage$^a$	Last semester	Last winter
All nights	1030 min	183	0.8%	1.4%	0.7%
Scheduled observing nights$^b$	975 min	127.5	1.1%	1.8%	0.8%
Technical nights	55 min	20.5	0.4%	1.1%	0.3%
Service nights$^c$	260 min	35	1.1%	2.6%	0.6%
Visitor instruments	0 min	14	0.0%	0.1%	0.0%
$^a$ Taking the average length of time within nautical twilight. Exact numbers for each night
are used when looking at `All nights'
$^b$ Excluding technical nights and visitor instruments
$^c$ Excluding service nights with SOFIN

This compares to a down time of 1.4% (1.8% on scheduled observing nights) in period 35 and 0.7% over all nights (0.8% on scheduled observing nights) in period 34. Of the 118 fault report in period 35, 80 reported no time lost, 34 reported $<$ 2 hrs lost, and 4 reported 2 or more hrs lost. Of the 117 fault report in period 34, 82 reported no time lost, 35 reported $<$ 2 hr lost, and none reported 2 or more hrs lost.

Apart from the continuously low down time, the only thing to notice is the relatively low number of fault reports during the last semester.